Fix undefined method `one?` when pushing to an existing merge requestsh-fix-issue-45152

An untested code path was triggering an Exception because Fixnum
doesn't have `one?` implemented in Rails, while arrays and collections
do.

Closes #45152

1 files changed, 14 insertions, 2 deletions

diff --git a/spec/mailers/notify_spec.rb b/spec/mailers/notify_spec.rb
index 971a88e9ee9..43e419cd7de 100644
--- a/spec/mailers/notify_spec.rb
+++ b/spec/mailers/notify_spec.rb
@@ -390,11 +390,11 @@ describe Notify do
         end
       end
 
-      describe 'that have new commits' do
+      shared_examples 'a push to an existing merge request' do
         let(:push_user) { create(:user) }
 
         subject do
-          described_class.push_to_merge_request_email(recipient.id, merge_request.id, push_user.id, new_commits: merge_request.commits)
+          described_class.push_to_merge_request_email(recipient.id, merge_request.id, push_user.id, new_commits: merge_request.commits, existing_commits: existing_commits)
         end
 
         it_behaves_like 'a multiple recipients email'
@@ -419,6 +419,18 @@ describe Notify do
           end
         end
       end
+
+      describe 'that have new commits' do
+        let(:existing_commits) { [] }
+
+        it_behaves_like 'a push to an existing merge request'
+      end
+
+      describe 'that have new commits on top of an existing one' do
+        let(:existing_commits) { [merge_request.commits.first] }
+
+        it_behaves_like 'a push to an existing merge request'
+      end
     end
 
     context 'for issue notes' do